Temperature-controlled UV-laser induced fabrication of planar polymeric waveguides

Integrated-optical waveguides may be written directly into the surface of a planar polymeric substrate by UV-excimer laser irradiation. The loss rate is relatively high due to the refractive index depth profile of waveguides produced in this way. The loss rate can be reduced significantly by use of a temperature-controlled fabrication process: during the UV-laser irradiation the polymeric substrate is heated in a controllable way by a hot plate. An explanation is given for this temperature-dependent effect.